This invention relates generally to X-ray imaging, and more particularly to a high frame-rate X-ray imaging system incorporating high speed image data acquisition and processing means enabling the X-ray imaging of anatomical vasculature in living patients in a highly effective and safe manner.
In connection with the study of spontaneous reperfusion during acute myocardial infarction, and for the purpose of determining a patient's condition during acute myocardial infarction, it is desirable to obtain images of the patient's coronary arterieis by X-ray techniques. The usual technique for obtaining such images is to introduce an appropriate X-ray opaque dye (contrast material) at relatively high concentrations into the heart arteries during direct X-ray examination. Because of the high concentration of contrast material required by this technique to obtain suitable images, it is necessary to introduce the contrast material directly to the heart arteries by coronary catheterization, a highly invasive procedure involving the insertion of a catheter tube through the patient's arteries. While effective, this procedure is generally undesirable because of the risks that it imposes on the patient.
It is also feasible to perform arterial X-ray imaging with a relatively low concentration of X-ray contrast material introduced by intravenous injection and using known digital computer image enhancement techniques, such as digital subtraction, to extract suitable arterial images. However, such techniques are ineffective for the detailed examination of the blood flow in the heart because the image data acquisition and processing systems heretofore available limit the maximum imaging rate to approximately 1.5 images per second. This rate is far too low in relation to the heart motion and other normally occurring tissue and bone movement to permit the acquisition of cardiac arterial images having sufficiently high temporal and spatial resolution to enable the precise determination of, for example, atherosclerotic plaque mass, regional myocardial X-ray contrast arrival time (perfusion), or global and regional systolic and diastolic ventricular function. Similar problems exist in the X-ray imaging of anatomical vasculature in other regions of a patient's body where the existence of motion artifact imposes limitations on the temporal and spatial resolution obtainable and causes misregistration when digital processing techniques are used to enhance the images.
Therefore, a need clearly exists for a high speed image data acquisition and processing system suitable for minimally invasive X-ray imaging of anatomical vasculature of living patients.